Niuafo'ou

Tonga's Isolated Caldera Shield in the Lau Basin

Elevation

260 m

Last Eruption

1946

Type

Shield

Country

Tonga

Location

Loading map...

Volcanic Hazards & Risk Assessment

Primary Hazards

Lava flows and fountaining
Volcanic gas emissions
Local explosive activity

Risk Level

Population at RiskLow

Infrastructure RiskHigh

Aviation RiskSignificant

Geological Composition & Structure

Rock Types

Primary

Unknown

Silica Content

Varied composition

Tectonic Setting

Unknown

Intraplate setting with hotspot or regional volcanic activity.

Age & Formation

Epoch

Unknown

Evidence

Unknown

Eruption Statistics & Analysis

Metric	Value	Global Ranking	Significance
Total Recorded Eruptions	Unknown	Low	Moderately active volcano
Maximum VEI	VEI Unknown	Minor	Local impact potential
Recent Activity	80 years ago	Historical	Recently active

Monitoring & Alert Status

Monitoring Networks

Global Volcanism Program

International eruption database

Current Status

Normal

No recent activity. Routine monitoring continues.

Authority Sources

Smithsonian GVP

Official volcano database

Related Volcanoes

Other Volcanoes in Tonga

Fonualei
Stratovolcano
Home Reef
Submarine Stratovolcano
Hunga Tonga-Hunga Ha'apai
Caldera

Interesting Facts

🌋

Niuafo'ou is known worldwide as 'Tin Can Island' because mail was historically sealed in tins and tossed overboard from ships to be retrieved by swimmers — one of the most unusual postal services in history.

🌋

The 1886 eruption reached VEI 4, an exceptionally powerful event for a small oceanic shield volcano only 260 m tall.

🌋

The 1946 eruption forced the evacuation of approximately 1,200 people to 'Eua island, 350 km away — one of the most significant volcanic displacements in Tongan history.

🌋

Niuafo'ou's 5-km-wide caldera is filled by Vai Lahi ('Big Lake'), whose bottom extends below sea level despite the lake surface being 23 m above sea level.

🌋

Nine eruptions occurred between 1853 and 1946, averaging roughly one per decade — yet the volcano has been quiet for nearly 80 years since, the longest gap in its recorded history.

🌋

Niuafo'ou lies 170 km west of the main Tofua volcanic arc, in the Lau Basin back-arc region — an unusual tectonic position for a frequently active volcano.

🌋

'Tin Can Mail' stamps and postal covers from Niuafo'ou are prized by philatelists worldwide and command significant prices among collectors.

🌋

The island has no harbor — its reef-fringed, cliff-lined coast prevents ships from docking, making evacuation logistics extremely difficult.

🌋

Small islands and pyroclastic cones within Vai Lahi lake testify to post-caldera explosive activity inside the flooded caldera.

🌋

The Pacific Plate subducts at the Tonga Trench at up to 24 cm per year — the fastest convergence rate on Earth — driving the volcanism that feeds Niuafo'ou.

Frequently Asked Questions

Is Niuafo'ou still active?

Yes, Niuafo'ou is classified as an active volcano. Its most recent confirmed eruption was in 1946, with uncertain activity reported from the caldera lake in 1985. The volcano produced nine eruptions between 1853 and 1946, averaging roughly one per decade. The current quiet period of nearly 80 years is the longest in recorded history but does not indicate the volcano has become extinct. The magmatic system beneath the caldera remains active, and volcanologists consider future eruptions plausible.

Why is it called Tin Can Island?

Niuafo'ou earned the nickname 'Tin Can Island' because of its unique mail delivery system. The island's coast is ringed by coral reefs and steep cliffs, preventing ships from docking. From the late 19th century through the mid-20th century, mail was sealed in waterproof tin cans (originally biscuit tins) and thrown overboard from passing ships. Strong swimmers from the island would swim out through the surf to retrieve the tins. Outgoing mail was taken to ships the same way. This extraordinary system made Niuafo'ou famous among stamp collectors and postal enthusiasts worldwide.

What happened in the 1946 eruption?

On September 9, 1946, an eruption began from fissure vents on Niuafo'ou's north flank. Lava flows advanced toward the island's main villages, destroying homes and gardens. Colonial authorities ordered the evacuation of most of the island's approximately 1,200 residents, who were transported by ship to the island of 'Eua, approximately 350 km to the south. The evacuation was one of the most significant volcanic displacements in Tongan history. Many families did not return for years, and the experience remains a defining event in the island's collective memory.

How big is Niuafo'ou?

Niuafo'ou is a nearly circular island approximately 8 km in diameter, but the habitable land forms only a ring 1-3 km wide around the central caldera lake. The highest point is just 260 m (853 ft) above sea level. The caldera lake, Vai Lahi, is 5 km wide and its bottom extends below sea level. The total area of the island (excluding the lake) is relatively small. However, the visible island is only the summit of a much larger submarine volcanic edifice that extends thousands of meters to the ocean floor.

Can you visit Niuafo'ou?

Niuafo'ou is accessible but extremely remote. Infrequent inter-island flights from Tongatapu operate when the small airstrip is serviceable, and supply ships visit periodically. There are no hotels or tourist infrastructure — visitors must arrange homestay accommodation with local families. The volcanic landscapes, caldera lake, and unique 'Tin Can Island' heritage are rewarding for adventurous travelers, but the logistics are challenging and require significant advance planning. Visitors should confirm transport options before traveling, as flights and ship schedules are irregular.

How many people live on Niuafo'ou?

Approximately 600-800 people currently live on Niuafo'ou, significantly fewer than the roughly 1,200 who inhabited the island before the 1946 evacuation. The population is spread across several small villages on the narrow caldera rim. Residents practice subsistence agriculture, growing coconuts, taro, and breadfruit, supplemented by fishing. The island's extreme isolation — 170 km from the nearest Tongan island — means that residents are largely self-sufficient and face significant challenges in accessing healthcare, education, and emergency services.